We estimate the impact of political coups and top-secret coup planning on asset prices. We use declassified CIA documents and daily stock price data to estimate the effect of private events on asset prices of partially nationalized US companies that stood to benefit from US backed coups. We find that stock markets react to actions classified as top-secret. Private events which raise the likelihood of a coup affect a continued rise in returns on affected assets. After incorporating the impact of private information events occurring before the coup, stock price reactions to coups are substantial.